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Saturday, October 18, 2014

Need help in troubleshooting CRT Television problem

I am one of your fans and I regularly visit your Blog for
technological update.

Sir recently I came across the CRT TV Problem that there is
intermittent fluctuation on the screen and picture shaking vertically (maybe
overloading).

I have opened the TV and found China make kit with

Toshiba IC.8893CRNG7D65.

I need your help to troubleshoot the problem sir,

can you help me if possible.

Thanking you-Yogesh

Humphrey:This problem is usually caused by faulty capacitor,
and from the picture you send me it most likely the capacitor which filter the
B+ voltage.

(From that picture i could see the capacitor highlighted has
a top slightly swollen that why I advised him to change it.)

Therefore directly change the capacitor I have highlighted
on the photo attached in this mail.

Kindly let me know if the problem is solved after changing
that capacitor.

When changing it, be sure to consider the polarity (+ to +
and - to -), working voltage and the capacitance value.

Waiting for your success report.

Humphrey-Kenya

Yogesh:Thanks a lot for reply , as directed by you I have
changed the capacitor value that is 22uf 160v but still problem is there I am getting +B voltages around 90 V DC. I
have checked for dry solder also but no success.

Humphrey:What is the voltage at the main capacitor?

Yogesh:I am getting 300 VDC at Main capacitor.

Humphrey:Check all the secondary output voltage after the
secondary diode and give me the figures

Most likely this is a capacitor fault problem...any
capacitor swollen on top or getting hot directly replace it.

Yogesh:As directed by you I have replaced the capacitor but
still the problem is same ( Picture
shaking intermittent vertically ) ,please find attached screen shot .

But now another problem is started TV is frequently getting
ON /OFF by itself.

One thing I have found when I removed whole circuit I found
that remote censor circuit wire is damaged may be shorted so I cut down the
wire and soldered directly on pcb but still same problem please guide.

(After seeing this i thought he was installing a new
board(universal TV board) to this Television)

Humphrey:Are you installing a new board?

Yogesh:No sir board is the same

Humphrey:I thought you are using 14 inch board for 21in
TV....try to adjust the B+ adjust preset if it has any?

Yogesh:As directed by you I am trying to adjust preset but
it is not giving any effect, so I have
decide to just take out preset and check sir I found this 2K preset OPEN It is
not giving any reading while testing with Multi-meter hence I replaced it with
new preset and TV is Back to the life.